Mercury–Organic Matter Interactions in Soils and Sediments: Angel or Devil?
Many studies have suggested that organic matter (OM) substantially reduces the bioavailability and risks of mercury (Hg) in soils and sediments; however, recent reports have supported that OM greatly accelerates Hg methylation and increases the risks of Hg exposure. This study aims to summarize the interactions between Hg and OM in soils and sediments and improve our understanding of the effects of OM on Hg methylation. The results show that OM characteristics, promotion of the activity of Hg-methylating microbial communities, and the microbial availability of Hg accounted for the acceleration of Hg methylation which increases the risk of Hg exposure. These three key aspects were driven by multiple factors, including the types and content of OM, Hg speciation, desorption and dissolution kinetics and environmental conditions.
KeywordsOrganic matter Methyl-mercury Hg Bioavailability Microbial methylation
This study was supported by the National Natural Science Foundation of China (Grant No. 41472124), PetroChina Innovation Foundation (Grant Nos. 2015D-5006-0210 and 2016D-5007-0702), Natural Science Foundation of Hubei Province (Grant Nos. 2016CFB178 and 2016CFB601), the Yangtze Youth Fund (Grant No. 2016cqr14) and China Scholarship Council (Grant Nos. 201708420108 and 201708420260).
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